TRANSFORMATION OF THE STRUCTURAL DEFECTS AND THE HYDROGEN STATE UPON HEAT-TREATMENT OF HYDROGENATED SILICON

Abstract

The paper presents the results of a study of the transformation of the structural defects, hydrogen state, and electro-physical properties of silicon treated in a hydrogen plasma. It is established that after the treatment of plasma (150°C) the bands with their peak maxima at 2095 and 2129 cm^–1 are observed in the Raman spectra. These peaks are associated with scattering on the vibrations of Si-H bonds. The subsequent heat treatment at 275°C results in the appearance of a band at 4153 cm^–1 related to the molecular hydrogen oscillations in a gaseous state. From a comparison of the data of Raman spectroscopy and scanning probe microscopy, it is found that as a result of the hydrogenation structural defects (platelets) with an average size of 43 nm and a surface density of 6.5 · 10⁹ cm^–2 are formed. Their appearance is due to the precipitation of hydrogen with the formation of Si-H bonds. After the heat treatment, inclusions filled with molecular hydrogen with an average size of 115 nm and a surface density of 1.7 · 10⁹ cm^–2 are formed. It is shown that the concentration of free charge carriers does not change after the plasma treatment and subsequent heat treatment.